The present invention relates to a control system for a bushing assembly used in the drawing of glass fibers and, in particular, is directed to such a system for use with a "bulk gas" drawing assembly of the type disclosed in U.S. Pat. No. 3,905,790 to Edward T. Strickland. In its more specific aspects, the invention is concerned with an improvement in the control system and bulk gas supply nozzle of our U.S. Pat. No. 3,986,853.
The system of our U.S. Pat. No. 3,986,853 relied upon a human operator to (1) sense the occurrence of a break-out of the fiber being drawn and (2) activate a control in response to the sensed condition. The activation of the control functioned to lower the temperature of the bushing assembly, increase the rate of flow of bulk gas against the orifice plate of the assembly, and reduce the drawing action of the collet used to draw the fiber from the plate. The system provided a manually operated air lance for startup and clearing of the plate.